There are only two known carboxyalkyl-substituted hydroxylamine compounds represented by formula (I) shown below. ##STR3## where L represents an alkylene group; A represents a hydrogen atom, a sulfo group, a carboxy group, a phosphono group, a trialkylammonio group, a hydroxy group, an amino group, an acyl group, a carbamoyl group, a sulfamoyl group, an alkoxycarbonyl group, or a cyano group; and R.sub.1, R.sub.2, and R.sub.3, which may be the same or different, each represent a hydrogen atom, an alkyl group, or an aryl group. These are compounds (III) and (IV). Their synthesis is described in the Tetrahedron Letters 3027-30 (1975) and German Patent 1,159,634 respectively: ##STR4##
Compound (III) is synthesized according to the two step process shown in reaction scheme (a): ##STR5##
The disadvantage of this synthesis process is that it requires two steps; a single step process would be preferrable.
The synthetic method of compound (IV) is described in German patent 1,159,634. This patent describes how compound (IV) is precipitated from the reaction mixture according to reaction scheme (b). However, an attempt to produce compound (IV) according to reaction scheme (b) did not yield compound (IV), but rather the following, compound (V) precipitated as crystals from the reaction mixture. ##STR6##
The formation ratio of compound (IV) to compound (V) in the reaction mixture was determined by NMR and found to be 17:83. Thus, compound (V) was formed as the main product, and the crystals of only compound (V) formed.
According to the method described in German Patent 1,159,634, compound (IV) can be prepared only as a by-product of the production of compound (V). Thus, this in not a technique for preparing compound (IV) at a high yield.
In order to use carboxyalkyl-substituted hydroxylamines represented by formula (I) described below, for processing solutions for photography, for example, a process is desired by which these compounds can be easily and directly prepared and by-products such as the compound (V) are avoided.